Method for manufacturing tow prepreg

Abstract

A tow prepreg manufacturing apparatus applies resin to an original tow of reinforcing fibers. The tow prepreg manufacturing apparatus includes an oiling roller, a scraper, a resin reservoir, a tube pump, and a controller. The oiling roller is supplied with resin while rotating at a predetermined rotation speed. The scraper adjusts the shape of the resin supplied onto the oiling roller. The resin reservoir supplies resin to the oiling roller. The tube pump discharges resin to the resin reservoir. The controller controls the tube pump so that the amount of resin held in the resin reservoir remains constant and controls the rotation speed of the oiling roller so that a resin content of a wound tow prepreg becomes equal to a target resin content.

The invention claimed is: 
     
       1. A method for manufacturing tow prepreg, the method comprising:
 supplying an oiling roller with resin from a resin reservoir; 
 moving an original tow of reinforcing fibers over the oiling roller to apply resin to the original tow; and 
 executing a resin discharge control and an oiling roller rotation speed control in parallel, wherein 
 the resin discharge control keeps the amount of resin supplied from the resin reservoir constant, 
 the oiling roller rotation speed control controls a rotation speed of the oiling roller to converge a resin content of a wound tow prepreg on a target resin content and adjust the amount of resin supplied to the original tow from the oiling roller, and 
 the oiling roller rotation speed control includes 
 calculating a resin content of the wound tow prepreg, and 
 feedback-controlling the rotation speed of the oiling roller in real time in accordance with the resin content of the wound tow prepreg and the target resin content so that the amount of resin supplied to the original tow from the oiling roller converges the resin content of the wound tow prepreg on the target resin content. 
 
     
     
       2. The method according to  claim 1 , wherein the resin discharge control includes
 detecting a liquid level height of the resin held in the resin reservoir, and 
 controlling the amount of resin delivered to the resin reservoir so that the detected liquid level height is held at a constant value. 
 
     
     
       3. The method according to  claim 1 , wherein the oiling roller rotation speed control includes
 detecting the weight of the resin delivered to the resin reservoir; 
 detecting the weight of the resin that falls from the oiling roller; 
 detecting a winding length of the wound tow prepreg, 
 calculating the amount of resin applied to the wound tow prepreg from the weight of resin delivered to the resin reservoir and the weight of resin that falls from the oiling roller, and 
 calculating the resin content of the wound tow prepreg from the winding length of the wound tow prepreg and the amount of resin applied to the wound tow prepreg. 
 
     
     
       4. The method according to  claim 1 , further comprising:
 preparing a resin reservoir including a groove surrounded by side walls and a bottom wall; 
 arranging the resin reservoir in contact with the oiling roller to form a cavity that holds resin between the oiling roller and the resin reservoir; and 
 supplying resin onto the oiling roller from a slit formed between the groove and the oiling roller. 
 
     
     
       5. The method according to  claim 4 , further comprising:
 narrowing a lateral width of a bottom surface of the resin reservoir in a stepped manner; and 
 rectifying a flow of the resin supplied to the oiling roller with the resin reservoir. 
 
     
     
       6. The method according to  claim 3 , further comprising:
 detecting the weight of resin that falls from a travel path of the tow prepreg at a downstream side of the oiling roller, 
 wherein the amount of resin applied to the wound tow prepreg is calculated from the weight of the resin delivered to the resin reservoir, the weight of the resin that falls from the oiling roller, and the weight of resin that falls from the travel path of the tow prepreg at the downstream side of the oiling roller. 
 
     
     
       7. A method for manufacturing tow prepreg, the method comprising:
 supplying an oiling roller with resin from a resin reservoir; 
 moving an original tow of reinforcing fibers over the oiling roller to apply resin to the original tow; and 
 executing a resin discharge control and an oiling roller rotation speed control in parallel, wherein 
 the resin discharge control keeps the amount of resin supplied from the resin reservoir constant, 
 the oiling roller rotation speed control controls a rotation speed of the oiling roller to converge a resin content of a wound tow prepreg on a target resin content and adjust the amount of resin supplied to the original tow from the oiling roller, and 
 the oiling roller rotation speed control includes 
 detecting the weight of the resin delivered to the resin reservoir; 
 detecting the weight of the resin that falls from the oiling roller; 
 detecting a winding length of the wound tow prepreg, 
 calculating the amount of resin applied to the wound tow prepreg from the weight of resin delivered to the resin reservoir and the weight of resin that falls from the oiling roller, and 
 calculating the resin content of the wound tow prepreg from the winding length of the wound tow prepreg and the amount of resin applied to the wound tow prepreg. 
 
     
     
       8. The method according to  claim 7 , wherein the resin discharge control includes
 detecting a liquid level height of the resin held in the resin reservoir, and 
 controlling the amount of resin delivered to the resin reservoir so that the detected liquid level height is held at a constant value. 
 
     
     
       9. The method according to  claim 7 , wherein the oiling roller rotation speed control includes
 calculating a resin content of the wound tow prepreg, and 
 feedback-controlling the rotation speed of the oiling roller in accordance with the resin content of the wound tow prepreg and the target resin content so that the amount of resin supplied to the original tow from the oiling roller converges the resin content of the wound tow prepreg on the target resin content. 
 
     
     
       10. The method according to  claim 7 , further comprising:
 preparing a resin reservoir including a groove surrounded by side walls and a bottom wall; 
 arranging the resin reservoir in contact with the oiling roller to form a cavity that holds resin between the oiling roller and the resin reservoir; and 
 supplying resin onto the oiling roller from a slit formed between the groove and the oiling roller. 
 
     
     
       11. The method according to  claim 10 , further comprising:
 narrowing a lateral width of a bottom surface of the resin reservoir in a stepped manner; and 
 rectifying a flow of the resin supplied to the oiling roller with the resin reservoir. 
 
     
     
       12. The method according to  claim 7 , further comprising:
 detecting the weight of resin that falls from a travel path of the tow prepreg at a downstream side of the oiling roller, 
 wherein the amount of resin applied to the wound tow prepreg is calculated from the weight of the resin delivered to the resin reservoir, the weight of the resin that falls from the oiling roller, and the weight of resin that falls from the travel path of the tow prepreg at the downstream side of the oiling roller. 
 
     
     
       13. The method according to  claim 1 , wherein
 feedback-controlling the rotation speed of the oiling roller in real time is achieved by executing Proportional-Integral-Differential (PID) control for each sampling time on the rotation speed of the oiling roller.